Oxidation process to produce a crude dry carboxylic acid product

ABSTRACT

Disclosed is a process to produce a dry purified carboxylic acid product comprising furan-2,5-dicarboxylic acid (FDCA). The process comprises oxidizing at least one oxidizable compound selected from the following group: 5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters (5-R(CO)OCH 2 -furfural where R=alkyl, cycloalkyl and aryl), 5-HMF ethers (5-R′OCH 2 -furfural, where R′=alkyl, cycloalkyl and aryl), 5-alkyl furfurals (5-R″-furfural, where R″=alkyl, cycloalkyl and aryl), mixed feed-stocks of 5-HMF and 5-HMF esters and mixed feed-stocks of 5-HMF and 5-HMF ethers and mixed feed-stocks of 5-HMF and 5-alkyl furfurals to generate a crude carboxylic acid slurry comprising FDCA, cooling a crude carboxylic acid slurry in cooling zone to form a cooled slurry stream. The cooled slurry stream is routed to a solid-liquid separation zone to generate a crude wet cake stream comprising FDCA that is dried in a drying zone to generate a dry carboxylic acid product stream comprising crude FDCA (cFDCA).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority to U.S. Provisional PatentApplication No. 61/694,982, filed on 30 Aug. 2012, the entire disclosureof which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a process to produce a carboxylic acidcomposition. The process comprises oxidizing at least one oxidizablecompound in an oxidizable raw material stream in the presence of anoxidizing gas stream, solvent stream, and at least one catalyst system.

More particularly, the process comprises oxidizing at least oneoxidizable compound selected from the following group:5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters (5-R(CO)OCH₂-furfuralwhere R=alkyl, cycloalkyl and aryl), 5-HMF ethers (5-R′OCH₂-furfural,where R′=alkyl, cycloalkyl and aryl), 5-alkyl furfurals (5-R″-furfural,where R″=alkyl, cycloalkyl and aryl), mixed feed-stocks of 5-HMF and5-HMF esters and mixed feed-stocks of 5-HMF and 5-HMF ethers and mixedfeed-stocks of 5-HMF and 5-alkyl furfurals in the presence of oxygen, asaturated organic acid solvent having from 2-6 carbon atoms, and acatalyst system at a temperature of about 100° C. to about 220° C. toproduce the carboxylic acid composition comprisingfuran-2,5-dicarboxylic acid to generate a crude carboxylic acid slurrycomprising FDCA, cooling a crude carboxylic acid slurry in cooling zoneto form a cooled slurry stream. The cooled slurry stream is routed to asolid-liquid separation zone to generate a crude wet cake streamcomprising FDCA that is dried in a drying zone to generate a drycarboxylic acid product stream comprising crude FDCA (cFDCA).

BACKGROUND OF THE INVENTION

Aromatic dicarboxylic acids, such as terephthalic acid and isophthalicacid, are used to produce a variety of polyester products. Importantexamples of which are poly(ethylene terephthalate) and its copolymers.These aromatic dicarboxylic acids are synthesized by the catalyticoxidation of the corresponding dialkyl aromatic compounds which areobtained from fossil fuels, which is disclosed in U.S. PatentApplication 2006/0205977 A1), which is herein incorporated by referenceto the extent it does not contradict the statements herein.

There is a growing interest in the use of renewable resources as feedstocks for the chemical industry mainly due to the progressive reductionof fossil reserves and their related environmental impacts.Furan-2,5-dicarboxylic acid (FDCA) is a versatile intermediateconsidered as a promising closest biobased alternative to terephthalicacid and isophthalic acid. Like aromatic diacids, FDCA can be condensedwith diols such as ethylene glycol to make polyester resins similar topolyethylene terephthalate (PET) (Gandini, A.; Silvestre, A. J; Neto, C.P.; Sousa, A. F.; Gomes, M. J. Poly. Sci. A 2009, 47, 295.). FDCA hasbeen prepared by oxidation of 5-(hydroxymethyl)furfural (5-HMF) underair using homogenous catalysts as disclosed in US2003/0055271 A1 and inPartenheimer, W.; Grushin, V. V. Adv. Synth. Catal. 2001, 343, 102-111.However, achieving high yields has proved difficult. A maximum of 44.8%yield using Co/Mn/Br catalysts system and a maximum of 60.9% yield wasreported using Co/Mn/Br/Zr catalysts combination.

Therefore, there is a need in the chemical industry for an inexpensiveand high yield process to make a crude FDCA.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates different embodiments of the invention wherein aprocess to produce a crude purified carboxylic acid 410 is provided.

DETAILED DESCRIPTION

It should be understood that the following is not intended to be anexclusive list of defined terms. Other definitions may be provided inthe foregoing description, such as, for example, when accompanying theuse of a defined term in context.

As used herein, the terms “a,” “an,” and “the” mean one or more.

As used herein, the term “and/or,” when used in a list of two or moreitems, means that any one of the listed items can be employed by itselfor any combination of two or more of the listed items can be employed.For example, if a composition is described as containing components A,B, and/or C, the composition can contain A alone; B alone; C alone; Aand B in combination; A and C in combination, B and C in combination; orA, B, and C in combination.

As used herein, the terms “comprising,” “comprises,” and “comprise” areopen-ended transition terms used to transition from a subject recitedbefore the term to one or more elements recited after the term, wherethe element or elements listed after the transition term are notnecessarily the only elements that make up the subject.

As used herein, the terms “having,” “has,” and “have” have the sameopen-ended meaning as “comprising,” “comprises,” and “comprise” providedabove.

As used herein, the terms “including,” “includes,” and “include” havethe same open-ended meaning as “comprising,” “comprises,” and “comprise”provided above.

The present description uses numerical ranges to quantify certainparameters relating to the invention. It should be understood that whennumerical ranges are provided, such ranges are to be construed asproviding literal support for claim limitations that only recite thelower value of the range as well as claim limitations that only recitethe upper value of the range. For example, a disclosed numerical rangeof 10 to 100 provides literal support for a claim reciting “greater than10” (with no upper bounds) and a claim reciting “less than 100” (with nolower bounds).

The present description uses specific numerical values to quantifycertain parameters relating to the invention, where the specificnumerical values are not expressly part of a numerical range. It shouldbe understood that each specific numerical value provided herein is tobe construed as providing literal support for a broad, intermediate, andnarrow range. The broad range associated with each specific numericalvalue is the numerical value plus and minus 60 percent of the numericalvalue, rounded to two significant digits. The intermediate rangeassociated with each specific numerical value is the numerical valueplus and minus 30 percent of the numerical value, rounded to twosignificant digits. The narrow range associated with each specificnumerical value is the numerical value plus and minus 15 percent of thenumerical value, rounded to two significant digits. For example, if thespecification describes a specific temperature of 62° F., such adescription provides literal support for a broad numerical range of 25°F. to 99° F. (62° F.+/−37° F.), an intermediate numerical range of 43°F. to 81° F. (62° F.+/−19° F.), and a narrow numerical range of 53° F.to 71° F. (62° F.+/−9° F.). These broad, intermediate, and narrownumerical ranges should be applied not only to the specific values, butshould also be applied to differences between these specific values.Thus, if the specification describes a first pressure of 110 psia and asecond pressure of 48 psia (a difference of 62 psi), the broad,intermediate, and narrow ranges for the pressure difference betweenthese two streams would be 25 to 99 psi, 43 to 81 psi, and 53 to 71 psi,respectively

In one embodiment of the invention, a process is provided to produce adry crude carboxylic acid 410 comprising furan-2,5-dicarboxylic acid(FDCA). Embodiments of the process are represented in FIG. 1. Theprocess comprises oxidizing at least one oxidizable compound in anoxidizable raw material stream 30 in the presence of an oxidizing gasstream 10, solvent stream 20, and at least one catalyst system. Theoxidizable raw material stream 30 comprises at least one oxidizablecompound suitable to produce a carboxylic acid composition 110comprising FDCA. The amount of FDCA in the carboxylic acid composition110 can range from greater than 10 by weight percent in the carboxylicacid composition 110, greater than 20 by weight percent in thecarboxylic acid composition 110, greater than 30 by weight percent inthe carboxylic acid composition 110. The carboxylic acid composition 110comprises FDCA and solvent.

In another embodiment of the invention, the process comprises oxidizingat least one oxidizable compound in an oxidizable raw material stream 30in the presence of an oxidizing gas stream 10, solvent stream 20, and atleast one catalyst system. The oxidizable raw material stream 30comprises at least one oxidizable compound selected from the groupconsisting of 5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters(5-R(CO)OCH₂-furfural where R=alkyl, cycloalkyl and aryl), 5-HMF ethers(5-R′OCH₂-furfural, where R′=alkyl, cycloalkyl and aryl), 5-alkylfurfurals (5-R″-furfural, where R″=alkyl, cycloalkyl and aryl), mixedfeedstocks of 5-HMF and 5-HMF esters, mixed feedstocks of 5-HMF and5-HMF ethers, mixed feedstocks of 5-HMF and 5-alkyl furfurals togenerate a carboxylic acid composition comprising FDCA. The processincludes cooling the carboxylic acid composition 110 in a cooling zone200. The cooled slurry stream 210 is routed to a solid-liquid separationzone 300 to generate a wet cake stream 310 comprising FDCA that is driedin a drying zone 400 to generate a dried, crude carboxylic acid 410comprising purified FDCA.

In one embodiment of the invention, a process is provided to produce adried, crude carboxylic acid 410 comprising dried,furan-2,5-dicarboxylic acid (FDCA) and comprises the following steps:

Step (a) comprises oxidizing at least one oxidizable compound in anoxidizable raw material stream 30 in the presence of an oxidizing gasstream 10, solvent stream 20, and at least one catalyst system in aprimary oxidation zone 100 which comprises at least one primary oxidizerreactor to produce a carboxylic acid composition 110 comprisingfuran-2,5-dicarboxylic (FDCA); wherein the oxidizable raw materialstream 30 comprises at least one oxidizable compound selected from thegroup consisting of 5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters(5-R(CO)OCH₂-furfural where R=alkyl, cycloalkyl and aryl), 5-HMF ethers(5-R′OCH₂-furfural, where R′=alkyl, cycloalkyl and aryl), 5-alkylfurfurals (5-R″-furfural, where R″=alkyl, cycloalkyl and aryl), mixedfeedstocks of 5-HMF and 5-HMF esters, mixed feedstocks of 5-HMF and5-HMF ethers, and mixed feedstocks of 5-HMF and 5-alkyl furfurals.Structures for the various oxidizable raw material compounds areoutlined below:

5-HMF feed is oxidized with elemental O2 in a multi-step reaction toform FDCA with 5-formyl furan-2-carboxylic acid (FFCA) as a keyintermediate eq 1. Oxidation of 5-(acetoxymethyl)furfural (5-AMF), whichcontains an oxidizable ester and aldehydes moieties, produces FDCA,FFCA, and acetic acid, eq 2. Similarly oxidation of5-(ethoxymethyl)furfural (5-EMF) produces FDCA, FFCA,5-(ethoxycarbonyl)furan-2-carboxylic acid (EFCA) and acetic acid, eq 3.

In one embodiment of this invention, streams routed to the primaryoxidation zone 100 comprises an oxidizing gas stream 10 comprisingoxygen and a solvent stream 20 comprising solvent, an oxidizable rawmaterial stream 30, and a catalyst system. Oxidizable raw materialstream 30 comprises a continuous liquid phase. In another embodiment ofthe invention, the oxidizable raw material stream 30, the oxidizing gasstream 10, the solvent stream 20 and the catalyst system can be fed tothe primary oxidization zone 100 as separate and individual streams orcombined in any combination prior to entering the primary oxidation zone100 wherein said feed streams may enter at a single location or inmultiple locations in the primary oxidization zone 100.

The carboxylic acid composition 110 comprises FDCA and FFCA. In anotherembodiment the FFCA in the carboxylic acid composition 110 ranges fromabout 0.1 wt % (weight percent) to about 4 wt % or 0.1 wt % to about 0.5wt %, or 0.1 wt % to about 1 wt %. In another embodiment of theinvention the carboxylic acid composition 110 comprises FDCA and FFCAand at least one of 2,5-diformylfuran in an amount ranging from 0 wt %to about 0.2 wt %, levulinic acid in an amount ranging from 0 wt % to0.5 wt %, succinic acid in an amount ranging from 0 wt % to 0.5 wt % andacetoxy acetic acid in an amount ranging from 0 wt % to 0.5 wt %.

In another embodiment of the invention the carboxylic acid composition110 comprises FDCA, FFCA and EFCA. In other embodiment of the inventionthe EFCA in the carboxylic acid composition 110 in an range from about0.05 wt % to 4 wt %, or about 1 wt % to 2 wt %.

The catalyst system comprises at least one catalyst suitable foroxidation. Any catalyst known in the art capable of oxidizing theoxidizable compound can be utilized. Example of suitable catalystscomprise at least one selected from, but are not limited to, cobalt,bromine and manganese compounds, which are soluble in the selectedoxidation solvent. In another embodiment of the invention, the catalystsystem comprises cobalt, manganese and bromine wherein the weight ratioof cobalt to manganese in the reaction mixture is from about 10 to about400 and the weight ratio of cobalt to bromine is from about 0.7 to about3.5.

The oxidizing gas stream comprises oxygen. Examples include, but are notlimited to, air and purified oxygen. The amount of oxygen in the primaryoxidation zone ranges from about 5 mole % to 45 mole %, 5 mole to 60mole % 5 mole % to 80 mole %.

Suitable solvents include water and the aliphatic solvents. In anembodiment of the invention, the solvents are aliphatic carboxylic acidswhich include, but are not limited to, aqueous solutions of C₂ to C₆monocarboxylic acids, e.g., acetic acid, propionic acid, n-butyric acid,isobutyric acid, n-valeric acid, trimethylacetic acid, caprioic acid,and mixtures thereof. In another embodiment of the invention, thesolvent is volatile under the oxidation reaction conditions to allow itto be taken as an off-gas from the oxidation reactor. In yet anotherembodiment of the invention the solvent selected is also one in whichthe catalyst composition is soluble under the reaction conditions.

The most common solvent used for the oxidation is an aqueous acetic acidsolution, typically having a concentration of 80 to 99 wt. %. Inespecially preferred embodiments, the solvent comprises a mixture ofwater and acetic acid which has a water content of 0% to about 15% byweight. Additionally, a portion of the solvent feed to the primaryoxidation reactor may be obtained from a recycle stream obtained bydisplacing about 80 to 90% of the mother liquor taken from the crudereaction mixture stream discharged from the primary oxidation reactorwith fresh, wet acetic acid containing about 0 to 15% water.

Suitable solvents include, but are not limited to, aliphaticmono-carboxylic acids, preferably containing 2 to 6 carbon atoms andmixtures thereof and mixtures of these compounds with water. Examples ofaliphatic mono-carboxylic acids, include, but are not limited to aceticacid.

Generally, the oxidation temperature can vary from about 100° C. toabout 220° C. and from about 110° C. to about 160° C.

In another embodiment of the invention, a process is provided to producefuran-2,5-dicarboxylic acid (FDCA) in high yields by liquid phaseoxidation that minimizes solvent and starting material loss throughcarbon burn. The process comprises oxidizing at least one oxidizablecompound in an oxidizable raw material stream 30 in the presence of anoxidizing gas stream 10, solvent stream 20, and at least one catalystsystem in a primary oxidation zone 100; wherein the oxidizable compoundis at least one selected from the group consisting of H(C═O)—R—(C═O)H,HOH2C—R—(C═O)H, and 5-(hydroxymethyl)furfural (5-HMF). The oxidizablecompound can be oxidized in a solvent comprising acetic acid with orwithout the presence of water with oxygen in the presence of a catalystsystem comprising cobalt, manganese and bromine, wherein the weightratio of cobalt to manganese in the reaction mixture is from about 10 toabout 400 and the weight ratio of cobalt to bromine is from about 0.7 toabout 3.5. Such a catalyst system with improved Co:Mn ratio can lead tohigh yield of FDCA. In this process, the oxidation temperature can varyfrom about 100° C. to about 220° C., or another range from about 110° C.to about 160° C., which can minimize carbon burn. The cobaltconcentration of the catalyst can range from about 1000 ppm to about6000 ppm, and the amount of manganese from about 2 ppm to about 600 ppm,and the amount of bromine from about 300 ppm to about 4500 ppm withrespect to the total weight of the liquid in the reaction medium of theprimary oxidation zone 100. As used herein, process temperature is thetemperature of the reaction mixture within the primary oxidation zonewhere liquid is present as the continuous phase. The primary oxidizerreactor will typically be characterized by a lower section where gasbubbles are dispersed in a continuous liquid phase. Solids can also bepresent in the lower section. In the upper section of the primaryoxidizer, gas is in the continuous phase and entrained liquid drops canalso be present.

In various embodiments of the invention, the catalyst compositionsemployed in the processes of the invention comprise cobalt atoms,manganese atoms, and bromine atoms, supplied by any suitable means, asfurther described below. The catalyst composition is typically solublein the solvent under reaction conditions, or it is soluble in thereactants fed to the oxidation zone. Preferably, the catalystcomposition is soluble in the solvent at 40° C. and 1 atm, and issoluble in the solvent under the reaction conditions.

The cobalt atoms may be provided in ionic form as inorganic cobaltsalts, such as cobalt bromide, cobalt nitrate, or cobalt chloride, ororganic cobalt compounds such as cobalt salts of aliphatic or aromaticacids having 2-22 carbon atoms, including cobalt acetate, cobaltoctanoate, cobalt benzoate, cobalt acetylacetonate, and cobaltnaphthalate.

The oxidation state of cobalt when added as a compound to the reactionmixture is not limited, and includes both the +2 and +3 oxidationstates.

The manganese atoms may be provided as one or more inorganic manganesesalts, such as manganese borates, manganese halides, manganese nitrates,or organometallic manganese compounds such as the manganese salts oflower aliphatic carboxylic acids, including manganese acetate, andmanganese salts of beta-diketonates, including manganeseacetylacetonate.

The bromine component may be added as elemental bromine, in combinedform, or as an anion. Suitable sources of bromine include hydrobromicacid, sodium bromide, ammonium bromide, potassium bromide, andtetrabromoethane. Hydrobromic acid, or sodium bromide may be preferredbromine sources.

In another embodiment of the invention, a process is provided forproducing furan-2,5-dicarboxylic acid (FDCA) in high yields by liquidphase oxidation that minimizes solvent and starting material lossthrough carbon burn. The process comprises oxidizing at least oneoxidizable compound in an oxidizable raw material stream 30 in thepresence of an oxidizing gas stream 10, solvent stream 20, and at leastone catalyst system in a primary oxidation zone 100; wherein theoxidizable compound is selected from the group consisting of5-(acetoxymethyl)furfural (5-AMF), 5-(ethoxymethyl)furfural (5-EMF),5-methyl furfural (5-MF); wherein the solvent stream 20 comprises aceticacid with or without the presence of water; wherein the catalyst systemcomprising cobalt, manganese and bromine, wherein the weight ratio ofcobalt to manganese in the reaction mixture ranges from about 10 toabout 400 and the weight ratio of cobalt to bromine is from about 0.7 toabout 3.5. The catalyst system with improved Co:Mn ratio can lead tohigh yield of FDCA. In this process, the oxidation temperature can varyfrom about 100° C. to about 220° C., or from about 110° C. to about 160°C. to minimize carbon burn. The cobalt concentration in the catalystsystem can range from about 500 ppm to about 6000 ppm, and the amount ofmanganese from about 2 ppm to about 600 ppm and the amount of brominefrom about 300 ppm to about 4500 ppm with respect to the total weight ofthe liquid in the reaction medium. Mixed feedstocks of 5-AMF and 5-HMFor 5-EMF and 5-HMF or 5-MF and 5-HMF or 5-AMF, 5-EMF and 5-HMF, withvarying ratios of the components can be used and similar results can beobtained.

In another embodiment of the invention, a process is provided forproducing furan-2,5-dicarboxylic acid (FDCA) in high yields by liquidphase oxidation that minimizes solvent and starting material lossthrough carbon burn. The process comprises oxidizing at least oneoxidizable compound in an oxidizable raw material stream 30 in thepresence of an oxidizing gas stream 10, solvent stream 20, and at leastone catalyst system in a primary oxidation zone 100; wherein saidoxidizable compound is 5-(hydroxymethyl)furfural (5-HMF); wherein saidsolvent stream comprises acetic acid with or without the presence ofwater; wherein said catalyst system comprising cobalt, manganese andbromine, wherein the weight ratio of cobalt to manganese in the reactionmixture is from about 10 to about 400. In this process, the temperaturecan vary from about 100° C. to about 220° C., from about 105° C. toabout 180° C., and from about 110° C. to about 160° C. The cobaltconcentration of the catalyst system can range from about 1000 ppm toabout 6000 ppm, and the amount of manganese can range from about 2 ppmto about 600 ppm, and the amount of bromine can range from about 300 ppmto about 4500 ppm with respect to the total weight of the liquid in thereaction medium.

In another embodiment of the invention, the process comprises oxidizingat least one oxidizable compound in an oxidizable raw material stream 30in the presence of an oxidizing gas stream 10, solvent stream 20, and atleast one catalyst system in a primary oxidation zone 100; wherein saidoxidizable compound is 5-(hydroxymethyl)furfural (5-HMF); wherein saidsolvent stream comprises a saturated organic acid having from 2-6 carbonatoms with or without the presence of water at a temperature of 100° C.to 220° C. to produce a dicarboxylic acid composition; wherein theprimary oxidation zone 100 comprises at least one primary oxidationreactor and wherein the catalyst system comprises cobalt in a range fromabout 500 ppm by weight to about 6000 ppm by weight with respect to theweight of the liquid in the reaction medium, manganese in an amountranging from about 2 ppm by weight to about 600 ppm by weight withrespect to the weight of the liquid in the reaction medium and brominein an amount ranging from about 300 ppm by weight to about 4500 ppm byweight with respect to the weight of the liquid in the reaction medium.

In another embodiment of the invention, when the oxidizable raw materialstream 30 comprises 5-HMF, then the cobalt to manganese ratio by weightis at least 10:1, 15:1, 20:1, 25:1, 30:1, 40:1, 50:1, 60:1, or 400 to 1.

In another embodiment of the invention, when the oxidizable materialstream 30 comprises at least one oxidizable compound selected from thegroup consisting of 5-HMF esters (5-R(CO)OCH₂-furfural where R=alkyl,cycloalkyl and aryl), 5-HMF ethers (5-R′OCH₂-furfural, where R′=alkyl,cycloalkyl and aryl), 5-alkyl furfurals (5-R″-furfural, where R″=alkyl,cycloalkyl and aryl), mixed feedstocks of 5-HMF and 5-HMF esters, mixedfeedstocks of 5-HMF and 5-HMF ethers, and mixed feed-stocks of 5-HMF and5-alkyl furfurals, the cobalt to manganese ratio by weight of thecatalyst system is at least 1:1, 10:1, 20:1, 50:1, 100:1, or 400:1.

In another embodiment of this invention, furan-2,5-dicarboxylic acid(FDCA) can be obtained by liquid phase oxidation of5-(hydroxymethyl)furfural (5-HMF), 5-(acetoxymethyl)furfural (5-AMF) and5-(ethoxymethyl)furfural (5-EMF) with molecular oxygen using Co/Mn/Brcatalyst system in acetic acid solvent. After the oxidation of5-HMF/5-AMF/5-EMF in presence of acetic acid, the FDCA precipitates outof solution. After filtration, washing with acetic acid and then withwater, and drying, solids were obtained with a minimum of 90%, 92%, 94%,96% FDCA content by weight.

In another embodiment of the invention, FDCA is obtained by liquid phaseoxidation of 5-HMF, 5-AMF and 5-EMF with molecular oxygen using Co/Mn/Brcatalyst system in acetic acid solvent. After the oxidation of5-HMF/5-AMF/5-EMF in acetic acid, the FDCA precipitates out of solution.After filtration, washing with acetic acid and then with water, anddrying, solids were obtained with a minimum of 96% FDCA content and amaximum b* of 15, 16, 17, 18, 19, or 20.

The b* is one of the three-color attributes measured on a spectroscopicreflectance-based instrument. The color can be measured by any deviceknown in the art. A Hunter Ultrascan XE instrument is typically themeasuring device. Positive readings signify the degree of yellow (orabsorbance of blue), while negative readings signify the degree of blue(or absorbance of yellow).

In another embodiment of the invention, a process is provided forproducing furan-2,5-dicarboxylic acid (FDCA) in minimum yields of 80% or85% or 90% or greater by liquid phase oxidation that minimizes solventand starting material loss through carbon burn. As used herein, yield isdefined as mass of FDCA obtained divided by the theoretical amount ofFDCA that should be produced based on the amount of raw material use.For example, if one mole or 126.11 grams of 5-HMF are oxidized, it wouldtheoretically generate one mole or 156.09 grams of FDCA. If for example,the actual amount of FDCA formed is only 150 grams, the yield for thisreaction is calculated to be =(150/156.09) times 100, which equals ayield of 96%. The same calculation applies for oxidation reactionconducted using 5-HMF derivatives or mixed feeds.

In another embodiment of this invention, a process is providedcomprising oxidizing at least one oxidizable compound in an oxidizableraw material stream 30 in the presence of an oxidizing gas stream 10,solvent stream 20, and at least one catalyst system in a primaryoxidation zone 100; wherein said oxidizable compound is selected fromthe group consisting of H(C═O)—R—(C═O)H, HOH2C—R—(C═O)H,5-(hydroxymethyl)furfural (5-HMF); wherein said solvent stream comprisesacetic acid with or without the presence of water; wherein said catalystsystem comprises cobalt, manganese and bromine, wherein the weight ratioof cobalt to manganese in the reaction mixture is from about 10 to about400 and the weight ratio of cobalt to bromine is from about 0.7 to about3.5. Such a catalyst system with improved Co:Mn and Co:Br ratio can leadto high yield of FDCA (minimum of 90%), decrease in the formation ofimpurities (measured by b*) causing color in the downstreampolymerization process while keeping the amount of CO and CO₂ in theoff-gas at a minimum.

The temperature in the primary oxidation zone can range from about 100°C. to about 220° C., and can range from about 110° C. to about 160° C.or can range from about 105° C. to about 180° C. or about 100° C. toabout 200° C., or about 100° C. to about 190° C. One advantage of thedisclosed primary oxidation conditions is low carbon burn as illustratedin Tables 1 to 3. Oxidizer off gas stream 120 is routed to the oxidizeroff gas treatment zone 800 to generate an inert gas stream 810, liquidstream 820 comprising water, and a recovered oxidation solvent stream830 comprising condensed solvent. In one embodiment, at least a portionof recovered oxidation solvent stream 830 is routed to wash solventstream 320 to become a portion of the wash solvent stream 320 for thepurpose of washing the solids present in the solid-liquid separationzone. In another embodiment, the inert gas stream 810 can be vented tothe atmosphere. In yet another embodiment, at least a portion of theinert gas stream 810 can be used as an inert gas in the process forinerting vessels and or used for convey gas for solids in the process.In another embodiment, at least a portion of the energy in stream 120 isrecovered in the form of steam and or electricity.

Step (b)

The crude carboxylic acid stream 110 comprising FDCA is routed tocooling zone 200 to generate a cooled crude carboxylic acid slurrystream 210 and a 1^(st) vapor stream 220 comprising oxidation solventvapor. The cooling of crude carboxylic slurry stream 110 can beaccomplished by any means known in the art; typically the cooling zone200 comprises a flash tank. In another embodiment, a portion of up to100% of the crude carboxylic acid slurry stream 110 is routed directlyto solid-liquid separation zone 300, thus said portion is not subjectedto cooling in cooling zone 200. The temperature of stream 210 can rangefrom 35° C. to 160° C., 45° C. to 120° C., and preferably from 55° C. to95° C.

Step (c) comprises isolating, washing, and dewatering solids present inthe cooled crude carboxylic acid slurry stream 210 in the solid-liquidseparation zone 300 to generate a crude carboxylic acid wet cake stream310 comprising FDCA. These functions may be accomplished in a singlesolid-liquid separation device or multiple solid-liquid separationdevices. The solid-liquid separation zone 300 comprises at least onesolid-liquid separation device capable of separating solids and liquids,washing solids with a wash solvent stream 320, and reducing the %moisture in the washed solids to less than 30 weight %, less than 20weight %, less than 15 weight %, and preferably less than 10 weight %.

Equipment suitable for the solid liquid separation zone 300 cantypically be comprised of, but not limited to, the following types ofdevices: centrifuges, cyclones, rotary drum filters, belt filters,pressure leaf filters, candle filters, and the like. The preferred solidliquid separation device for the solid liquid separation zone 300 is arotary pressure drum filter. The temperature of cooled crude carboxylicacid slurry steam 210 which is routed to the solid-liquid separationzone 300 can range from 50° C. to 140° C., 70° C. to 120° C., and ispreferably from 75° C. to 95° C. Wash solvent stream 320 comprises aliquid suitable for displacing and washing oxidizer mother liquor fromthe solids.

In one embodiment of the invention, a suitable wash solvent comprisesacetic acid. In another embodiment, a suitable wash solvent comprisesacetic acid and water. In yet another embodiment, a suitable washsolvent comprises water up to 100% water. The temperature of the washsolvent can range from 20° C. to 135° C., 40° C. to 110° C., andpreferably from 50° C. to 90° C. The amount of wash solvent used isdefined as the wash ratio and equals the mass of wash divided by themass of solids on a batch or continuous basis. The wash ratio can rangefrom about 0.3 to about 5, about 0.4 to about 4, and preferably fromabout 0.5 to 3.

After solids are washed in the solid liquid separation zone, they aredewatered. The term dewatering is defined as the reduction of solventfrom the wet cake and does not require that the solvent be water orcontain water. Dewatering involves reducing the mass of moisture presentwith the solids to less than 30% by weight, less than 25% by weight,less than 20% by weight, and most preferably less than 15% by weightresulting in the generation of a crude carboxylic acid wet cake stream310 comprising FDCA. In one embodiment, dewatering is accomplished in afilter by passing a stream comprising gas through the solids to displacefree liquid after the solids have been washed with a wash solvent. In anembodiment, dewatering of the wet cake solids in solid-liquid separationzone 300 can be implemented before washing and after washing the wetcake solids in zone 300 to minimize the amount of oxidizer solventpresent in the wash liquor stream 340. In another embodiment, dewateringis achieved by centrifugal forces in a perforated bowl or solid bowlcentrifuge.

Mother liquor steam 330 generated in solid-liquid separation zone 300comprises oxidation solvent, catalyst, and impurities. From 5% to 95%,from 30% to 90%, and most preferably from 40 to 80% of mother liquorpresent in the crude carboxylic acid stream 110 is isolated insolid-liquid separation zone 300 to generate mother liquor stream 330resulting in dissolved matter comprising impurities present motherliquor stream 330 not going forward in the process. In one embodiment, aportion of mother liquor stream 330 is routed to a purge zone a portionis at least 5 weight %, at least 25 weight %, at least 45 weight %, atleast 55 weight % at least 75 weight %, at least 90 weight %. In anotherembodiment, at least a portion is routed back to the primary oxidationzone wherein a portion is at least 5 weight %. In yet anotherembodiment, at least a portion of mother liquor stream 330 is routed toa purge zone and to the primary oxidation zone wherein a portion is atleast 5 weight %. In one embodiment, purge zone 700 comprises anevaporative step to separate oxidation solvent from stream 330 byevaporation.

Wash liquor stream 340 is generated in the solid-liquid separation zone300 and comprises a portion of the mother liquor present in stream 210and wash solvent wherein the ratio of mother liquor mass to wash solventmass is less than 3 and preferably less than 2. In an embodiment, atleast a portion of wash liquor stream 340 is routed to oxidation zone100 wherein a portion is at least 5 weight %. In an embodiment, at leasta portion of wash liquor stream is routed to purge zone 700 wherein aportion is at least 5 weight %. In another embodiment, at least aportion of wash liquor stream is routed to oxidation zone 100 and purgezone 700 wherein a portion is at least 5 weight %.

In another embodiment at least a portion of crude carboxylic acid slurrystream 110 up to 100 weight % is routed directly to solid-liquidseparation zone 300, thus said portion will bypass the cooling zone 200.

In this embodiment, feed to solid-liquid separation zone 300 comprisesat least a portion of crude carboxylic slurry stream 110 and washsolvent stream 320 to generate a crude carboxylic acid wet cake stream310 comprising FDCA. Solids in the feed slurry are isolated, washed, anddewatered in solid-liquid separation zone 300. These functions may beaccomplished in a single solid-liquid separation device or multiplesolid-liquid separation devices. The solid-liquid separation zonecomprises at least one solid-liquid separation device capable ofseparating solids and liquids, washing solids with a wash solvent stream320, and reducing the % moisture in the washed solids to less than 30weight %, less than 20 weight %, less than 15 weight %, and preferablyless than 10 weight %. Equipment suitable for the solid liquidseparation zone can typically be comprised of, but not limited to, thefollowing types of devices: centrifuge, cyclone, rotary drum filter,belt filter, pressure leaf filter, candle filter, and the like. Thepreferred solid liquid separation device for the solid liquid separationzone is a continuous rotary pressure drum filter. The temperature of thecrude carboxylic acid slurry feed steam which is routed to thesolid-liquid separation zone 300 can range from 40° C. to 210° C., 60°C. to 170, ° C. and is preferably from 80° C. to 160° C. The wash stream320 comprises a liquid suitable for displacing and washing mother liquorfrom the solids. In one embodiment, a suitable wash solvent comprisesacetic acid and water. In another embodiment, a suitable wash solventcomprises water up to 100% water. The temperature of the wash solventcan range from 20° C. to 180° C., 40° C. and 150° C., and preferablyfrom 50° C. to 130° C. The amount of wash solvent used is defined as thewash ratio and equals the mass of wash divided by the mass of solids ona batch or continuous basis. The wash ratio can range from about 0.3 toabout 5, about 0.4 to about 4, and preferably from about 0.5 to 3. Aftersolids are washed in the solid liquid separation zone, they aredewatered. Dewatering involves reducing the mass of moisture presentwith the solids to less than 30% by weight, less than 25% by weight,less than 20% by weight, and most preferably less than 15% by weightresulting in the generation of a crude carboxylic acid wet cake stream310. In one embodiment, dewatering is accomplished in a filter bypassing a gas stream through the solids to displace free liquid afterthe solids have been washed with a wash solvent. In another embodiment,dewater of the wet cake in solid-liquid separation zone 300 can beimplemented before washing and after washing the solids in zone 300 tominimize the amount of oxidizer solvent present in the wash liquorstream 340 by any method known in the art. In yet another embodiment,dewatering is achieved by centrifugal forces in a perforated bowl orsolid bowl centrifuge.

Mother liquor steam 330 generated in solid-liquid separation zone 300comprising oxidation solvent, catalyst, and impurities. From 5% to 95%,from 30% to 90%, and most preferably from 40 to 80% of mother liquorpresent in the crude carboxylic acid stream 110 is isolated insolid-liquid separation zone 300 to generate mother liquor stream 330resulting in dissolved matter comprising impurities present motherliquor stream 330 not going forward in the process. In one embodiment, aportion of mother liquor stream 330 is routed to a purge zone a portionis at least 5 weight %, at least 25 weight %, at least 45 weight %, atleast 55 weight % at least 75 weight %, at least 90 weight %. In anotherembodiment, at least a portion is routed back to the primary oxidationzone wherein a portion is at least 5 weight %. In yet anotherembodiment, at least a portion of mother liquor stream 330 is routed toa purge zone and to the primary oxidation zone wherein a portion is atleast 5 weight %. In one embodiment, purge zone 700 comprises anevaporative step to separate oxidation solvent from stream 330 byevaporation.

Wash liquor stream 340 is generated in the solid-liquid separation zone300 and comprises a portion of the mother liquor present in stream 210and wash solvent wherein the ratio of mother liquor mass to wash solventmass is less than 3 and preferably less than 2. In an embodiment, atleast a portion of wash liquor stream 340 is routed to oxidation zone100 wherein a portion is at least 5 weight %. In an embodiment, at leasta portion of wash liquor stream is routed to purge zone 700 wherein aportion is at least 5 weight %. In another embodiment, at least aportion of wash liquor stream is routed to oxidation zone 100 and purgezone 700 wherein a portion is at least 5 weight %.

Step (d) Oxidizer mother liquor stream 330 comprises oxidation solvent,catalyst, soluble intermediates, and soluble impurities. It is desirableto recycle directly or indirectly at least a portion of the catalyst andoxidation solvent present in mother liquor stream 330 back to oxidationzone 100 wherein a portion is at least 5% by weight, at least 25%, atleast 45%, at least 65%, at least 85%, at least 95%. Direct recycling atleast a portion of the catalyst and oxidation solvent present in motherliquor stream 330 comprises directly routing a portion of stream 330 tooxidizer zone 100. Indirect recycling at least a portion of the catalystand oxidation solvent present in mother liquor stream 330 to oxidationzone 100 comprises routing at least a portion of stream 330 to at leastone intermediate zone wherein stream 330 is treated to generate a streamor multiple streams comprising oxidation solvent and or catalyst thatare routed directly to oxidation zone 100. A purge zone can be utilizedto separate components of stream 330 for recycle to the process whilealso isolating those components not to be recycled but rather removedfrom the process as a purge stream.

Impurities in stream 330 can originate from one or multiple sources.Impurities in stream 330 comprise impurities introduced into the processby feeding streams to oxidation zone 100 that comprise impurities. Animpurity is defined as any molecule not required for the properoperation of oxidation zone 100. For example, oxidation solvent, acatalyst system, a gas comprising oxygen, and oxidizable raw materialcomprising at least one compound selected from the group of formula:5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters (5-R(CO)OCH₂-furfuralwhere R=alkyl, cycloalkyl and aryl), 5-HMF ethers (5-R′OCH₂-furfural,where R′=alkyl, cycloalkyl and aryl), 5-alkyl furfurals (5-R″-furfural,where R″=alkyl, cycloalkyl and aryl), mixed feed-stocks of 5-HMF and5-HMF esters and mixed feed-stocks of 5-HMF and 5-HMF ethers and mixedfeed-stocks of 5-HMF and 5-alkyl furfurals comprise molecules arerequired for the proper operation of oxidation zone 100 and are notconsidered impurities. Also, chemical intermediates formed in oxidationzone 100 that lead to or contribute to chemical reactions that lead todesired products are not considered impurities. Oxidation by-productsthat do not lead to desired product are defined as impurities.Impurities may enter oxidation zone 100 through recycle streams routedto oxidation zone 100 or by impure raw material streams fed to oxidationzone 100.

In one embodiment, it is desirable to isolate a portion of theimpurities from mother liquor stream 330 and purge or remove them fromthe process as purge stream 720. From 5% to 100% by weight, of motherliquor stream 330 generated in solid-liquid separation zone 300 isrouted to purge zone 700 wherein a portion of the impurities present instream 330 are isolated and exit the process as purge stream 720,wherein a portion is 5% by weight or greater, 25% by weight or greater,45% by weight or greater, 65% by weight or greater, 85% by weight orgreater, 95% by weight or greater. Recovered solvent stream 710comprises oxidation solvent and catalyst isolated from stream 330 and isrecycled to the process. In one embodiment, recovered solvent stream 710is recycled to oxidation zone 100 and contains greater than 30%, greaterthan 50%, greater than 80%, or greater than 90% of the catalyst thatentered the mother liquor purge zone 700 in stream 330. In anotherembodiment, at least a portion of mother liquor stream 330 is routeddirectly to oxidation zone 100 without first being treated in purge zone700. In one embodiment, purge zone 700 comprises an evaporative step toseparate oxidation solvent from stream 330 by evaporation.

Step (e) comprises drying crude carboxylic acid wet cake stream 310 in adryer zone to generate a dry crude carboxylic acid stream 410 comprisingFDCA and a 2nd vapor stream 420 comprising wash solvent. In oneembodiment, vapor stream 420 comprises wash solvent vapor. In anotherembodiment, vapor stream 420 comprises oxidation solvent and washsolvent. The drying zone comprises at least one dryer and can beaccomplished by any means known in the art that is capable ofevaporating at least 10% of the volatiles remaining in the low impuritywet cake stream 310 to produce the dry crude carboxylic acid stream 410comprising FDCA and a vapor stream 420. For example, indirect contactdryers including a rotary steam tube dryer, a Single Shaft Porcupine®dryer, and a Bepex Solidaire® dryer. Direct contact dryers including afluid bed dryer, a ring dryer, and drying in a convey line can be usedfor drying to produce stream 410. The dried crude carboxylic acid stream410 comprising FDCA can be a carboxylic acid composition with less than8% moisture, preferably less than 5% moisture, and more preferably lessthan 1% moisture, and even more preferably less than 0.5%, and yet morepreferably less than 0.1%.

In one embodiment, a vacuum system can be utilized to pull vapor stream420 from drying zone 400. If a vacuum system is used in this fashion,the pressure of stream 420 at the dryer outlet can range from about 760mmHg absolute to about 400 mmHg absolute, from about 760 mmHg absoluteto about 600 mmHg absolute, from about 760 mmHg absolute to about 700mmHg absolute, from about 760 mmHg absolute to about 720 mmHg absolute,from about 760 mmHg absolute to about 740 mmHg absolute, whereinpressure is measured in mmHg above absolute vacuum. The contents of theconduit between solid-liquid separation zone 300 and drying zone 400utilized to transfer wet cake stream 410 comprises wet cake stream 410and gas wherein gas is the continuous phase. In one embodiment, thedifference in pressure where wet cake stream 410 exits solid liquidseparation zone 300 and where vapor stream 420 exits drying zone 400 isless than 2 psi, less than 0.8 psi, and preferably less than 0.4 psi. Inone embodiment, a rotary air-lock valve is used to discharge solids fromthe dryer zone to a location outside the dryer zone that has a higherpressure than the drying zone. In this embodiment, the rotary air-lockvalve serves to meter dry solids from the dryer into a higher pressureenvironment.

In an embodiment of the invention, the dried crude carboxylic acidstream 410 has a b* less than about 20.0. In another embodiment of theinvention, the b* color of the dried carboxylic acid stream 410 is lessthan about 9.0. In another embodiment of the invention, the b* color ofthe dried carboxylic acid stream 410 is less than about 5.0. The b*color is one of the three-color attributes measured on a spectroscopicreflectance-based instrument. A Hunter Ultrascan XE instrument inreflectance mode is typically the measuring device. Positive readingssignify the degree of yellow (or absorbance of blue), while negativereadings signify the degree of blue (or absorbance of yellow).

One function of drying zone 400 is to remove by evaporation oxidationsolvent comprising a mono-carboxylic acid with 2 to 6 carbons that canbe present in the crude carboxylic acid wet cake stream 310. The %moisture in crude carboxylic acid wet cake stream 310 typically rangesfrom 4.0% by weight to 30% by weight depending on the operationconditions of the solid-liquid separation zone 300. If for example, theliquid portion of stream 310 is about 90% acetic acid, the amount ofacetic acid present in stream 310 can range from about 3.6 weight % to27 weight %.

It should be appreciated that the process zones previously described canbe utilized in any other logical order to produce the dried, purifiedcarboxylic acid 710. It should also be appreciated that when the processzones are reordered that the process conditions may change. It is alsounderstood that all percent values are weight percents.

Since numerous modifications and changes will readily occur to thoseskilled in the art, it is not desired to limit this invention to theexact process and operations illustrated and described above, andaccordingly all suitable modifications and equivalents may be resortedto, falling within the scope of the invention

EXAMPLES

This invention can be further illustrated by the following examples ofembodiments thereof, although it will be understood that these examplesare included merely for the purposes of illustration and are notintended to limit the scope of the invention unless otherwisespecifically indicated.

Air oxidation of 5-HMF/5-AMF/5-EMF using cobalt, manganese and ionicbromine catalysts system in acetic acid solvent were conducted. Afterreaction the heterogeneous mixture was filtered to isolate the crudeFDCA. The crude FDCA was washed with acetic acid two times and thentwice with DI water. The washed crude FDCA was oven dried at 110° C.under vacuum overnight. The solid and the filtrate were analyzed by GasChromatography using BSTFA derivatization method. b* of the solid wasmeasured using a Hunter Ultrascan XE instrument. The Off-gas wasanalyzed for CO and CO₂ by ND-1R (ABB, Advanced Optima) and O₂ by aparamagnetism detection system (Servomex, 1440 Model).

As shown in Tables 1 to 3 we have discovered conditions that to generateyields of FDCA up to 89.4%, b*<6, and low carbon burn (<0.00072 mol/minCO+CO₂)

TABLE 1 Results from semi-batch reactions using 5-HMF feed.* Bromide Coconc Mn conc Br conc yield of yield of CO (total CO₂ (total CO_(X) colorExample source (ppm) (ppm) (ppm) FDCA (%) FFCA (%) mol) mol) (mol/min)(b*) 1a solid NaBr 2000 93.3 3000 81.6 0.81 0.013 0.078 0.000758 13.911b solid NaBr 2000 93.3 3000 82.6 0.87 0.013 0.092 0.000875 14.14 1caqueous HBr 2000 93.3 3000 89.4 0.58 0.003 0.061 0.000533 5.85 1daqueous HBr 2000 93.3 3000 88.6 0.8 0.0037 0.061 0.000539 6.18 *P = 130psig, CO_(x) (mol/min) = CO (mol/min) + CO2 (mol/min).

TABLE 2 Results from semi-batch reactions using 5-AMF feed.* Co conc Mnconc Br conc Temperature % yield % yield CO (total CO2 (total CO_(x)color Example (ppmw) (ppmw) (ppmw) (° C.) of FDCA of FFCA mol) mol)(mol/min) (b*) 2a 2500 116.8 2500 130 88.2 0.25 0.0052 0.08 0.00071 4.42b 2000 93.5 3000 130 90.2 0.16 0.005 0.046 0.000425 6.8 *P = 130 psig,CO_(x) (mol/min) = CO (mol/min) + CO2 (mol/min).

TABLE 3 Results from semi-batch reactions using 5-EMF feed.* Co conc Mnconc Br conc Temperature % yield % yield % yield CO (total CO2 (totalCO_(x) color Example (ppmw) (ppmw) (ppmw) (° C.) of FDCA of FFCA of EFCAmol) mol) (mol/min) (b*) 3a 2500 116.8 2500 130 88.8 0.02 0.225 0.0080.068 0.000633333 3.97 3b 2000 93.5 3000 130 88.0 0.09 0.43 0.008 0.0780.000716667 2.48 3c 2000 93.5 3000 105 86.0 2.92 1.4 0.005 0.0460.000425 6.66 3d 2500 116.8 2500 130 87.4 0.42 1.3 0.009 0.0640.000608333 2.74 *P = 130 psig, CO_(x) (mol/min) = CO (mol/min) + CO2(mol/min).

Analytical

Gas Chromatographic Method

Process samples were analyzed using a Shimadzu gas chromatograph Model2010 (or equivalent) equipped with a split/heated injector (300° C.) anda flame ionization detector (300° C.). A capillary column (60 meter×0.32mm ID) coated with (6% cyanopropylphenyl)-methylpolysiloxane at 1.0 μmfilm thickness (such as DB-1301 or equivalent) was employed. Helium wasused as the carrier gas with an initial column head pressure of 29.5 psiand an initial column flow of 3.93 mL/minute while the carrier gaslinear velocity of 45 cm/second was maintained constant throughout theentire oven temperature program. The column temperature was programmedas follows: The initial oven temperature was set at 80° C. and was heldfor 6 minutes, the oven was ramped up to 150° C. at 4° C./minute and washeld at 150° C. for 0 minute, the oven was ramped up to 240° C. at 10°C./minute and was held at 240° C. for 5 minutes, then the oven wasramped up to 290° C. at 10° C./minute and was held at 290° C. for 17.5minutes (the total run time was 60 mins). 1.0-μl of the prepared samplesolution was injected with a split ratio of 40:1. EZ-Chrom Elitechromatography data system software was used for data acquisition anddata processing. The sample preparation was done by weighing 0.1 g(accurate to 0.1 mg) of sample in a GC vial and adding 200.0 μl ISTDsolution (1% by volume of decane in pyridine) and 1000 μl of BSTFA(N,O-bis(trimethylsilyl)trifluoroacetamide) with 1% TMSCl(trimethylchlorosilane) to the GC vial. The content was heated at 80° C.for 30 minutes to ensure complete derivatization. 1.0-μl of thisprepared sample solution was injected for GC analysis.

Color Measurement.

1) Assemble the Carver Press die as instructed in the directions—placethe die on the base and place the bottom 40 mm cylinder polished sideface-up.2) Place a 40 mm plastic cup (Chemplex Plasticup, 39.7×6.4 mm) into thedie.3) Fill the cup with the sample to be analyzed. The exact amount ofsample added is not important.4) Place the top 40 mm cylinder polished side face-down on the sample.5) Insert the plunger into the die. No “tilt” should be exhibited in theassembled die.6) Place the die into the Carver Press, making sure that it is near thecenter of the lower platen. Close the safety door.7) Raise the die until the upper platen makes contact with the plunger.Apply >20,000 lbs. pressure. Then allow the die to remain under pressurefor approximately 3 minutes (exact time not critical).8) Release the pressure and lower the lower platen holding the die.9) Disassemble the die and remove the cup. Place the cup into a labeledplastic bag (Nasco Whirl-Pak 4 oz.).10) Using a HunterLab Colorquest XE colorimeter, create the followingmethod (Hunterlab EasyQuest QC software, version 3.6.2 or later)

Mode: RSIN-LAV (Reflectance Specular Included-Large Area View)Measurements: CIE L* a* b* CIE X Y Z

11) Standardize the instrument as prompted by the software using thelight trap accessory and the certified white tile accessory pressedagainst the reflectance port.12) Run a green tile standard using the certified white tile and comparethe CIE X, Y, and Z values obtained against the certified values of thetile. The values obtained should be ±0.15 units on each scale of thestated values.13) Analyze the sample in the bag by pressing it against the reflectanceport and obtaining the spectrum and L*, a*, b* values. Obtain duplicatereadings and average the values for the report.

CLAIMS NOT LIMITED TO DISCLOSED EMBODIMENTS

The preferred forms of the invention described above are to be used asillustration only, and should not be used in a limiting sense tointerpret the scope of the present invention. Modifications to theexemplary embodiments, set forth above, could be readily made by thoseskilled in the art without departing from the spirit of the presentinvention.

The inventors hereby state their intent to rely on the Doctrine ofEquivalents to determine and assess the reasonably fair scope of thepresent invention as it pertains to any apparatus not materiallydeparting from but outside the literal scope of the invention as setforth in the following claims.

We claim:
 1. A process to produce a carboxylic acid composition, saidprocess comprising: (a) oxidizing in an primary oxidation zone anoxidizable compound in a oxidizable raw material stream in the presenceof a solvent stream, an oxidizing gas stream, and a catalyst system,wherein said an oxidizable raw material stream comprises at least onecompound selected from the group consisting of 5-(hydroxymethyl)furfural(5-HMF), 5-HMF esters (5-R(CO)OCH₂-furfural where R=alkyl, cycloalkyland aryl), 5-HMF ethers (5-R′OCH₂-furfural, where R′=alkyl, cycloalkyland aryl), 5-alkyl furfurals (5-R″-furfural, where R″=alkyl, cycloalkyland aryl), mixed feedstocks of 5-HMF and 5-HMF esters, mixed feedstocksof 5-HMF and 5-HMF ethers, and mixed feedstocks of 5-HMF and 5-alkylfurfurals to produce a carboxylic acid composition comprisingfuran-2,5-dicarboxylic acid (FDCA); (b) routing said carboxylic acidcomposition to a cooling zone; (c) routing cooled carboxylic acidcomposition to a solid-liquid separation zone generating a mother liquorstream and wet carboxylic acid composition; (d) routing the wetcarboxylic acid composition to a drying zone to produce isolated crudecarboxylic acid composition.
 2. A process according to claim 1 wherein aportion of said displaced mother liquid stream is routed to a purge zoneto generate a recovered solvent stream comprising solvent and catalyst.3. A process according to claim 1 wherein said oxidizing is accomplishedin the presence of a catalyst system at a temperature of about 100° C.to about 220° C. to produce said carboxylic acid composition; whereinsaid primary oxidation zone comprises at least one oxidation reactor andwherein said carboxylic acid composition comprisesfuran-2,5-dicarboxylic acid; wherein said catalyst system comprisescobalt, manganese and bromine; and wherein the yield offuran-2,5-dicarboxylic acid (FDCA) is greater than 60%.
 4. A processaccording to claim 1 wherein an offgas from said primary oxidation zoneis routed to an oxidizer offgas treatment zone.
 5. A process accordingto claim 1 wherein said oxidizable raw material stream comprises atleast one compound selected from the group consisting of5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters (5-R(CO)OCH₂-furfuralwhere R=alkyl, cycloalkyl and aryl), 5-HMF ethers (5-R′OCH₂-furfural,where R′=alkyl, cycloalkyl and aryl), and wherein the yield offuran-2,5-dicarboxylic acid is greater than 70%.
 6. A process accordingto claim 1 wherein said oxidizable raw material stream comprises atleast one selected from the group consisting of5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters (5-R(CO)OCH₂-furfuralwhere R=alkyl, cycloalkyl and aryl), 5-HMF ethers (5-R′OCH₂-furfural,where R′=alkyl, cycloalkyl and aryl), and wherein the yield offuran-2,5-dicarboxylic acid is greater than 80%.
 7. A process accordingto claim 1 wherein said oxidizable raw material stream comprises atleast one selected from the group consisting of5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters (5-R(CO)OCH₂-furfuralwhere R=alkyl, cycloalkyl and aryl), 5-HMF ethers (5-R′OCH₂-furfural,where R′=alkyl, cycloalkyl and aryl), and wherein the yield offuran-2,5-dicarboxylic acid is greater than 90%.
 8. A process accordingto claim 1 wherein said oxidizable raw material stream comprises atleast one selected from the group consisting of5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters (5-R(CO)OCH₂-furfuralwhere R=alkyl, cycloalkyl and aryl), 5-HMF ethers (5-R′OCH₂-furfural,where R′=alkyl, cycloalkyl and aryl), and wherein the yield offuran-2,5-dicarboxylic acid is greater than 95%.
 9. A process accordingto claim 8 wherein said primary oxidation zone comprises a catalystsystem wherein said catalyst system comprises cobalt in a range fromabout 500 ppm to about 6000 ppm with respect to the weight of the liquidin the primary oxidation zone, manganese in an amount ranging from about2 ppm to about 600 ppm by weight with respect to the weight of theliquid in the primary oxidation zone and bromine in an amount rangingfrom about 300 ppm to about 4500 ppm by weight with respect to theweight of the liquid in the primary oxidation zone.
 10. A processaccording to claim 8 wherein said primary oxidation zone comprises acatalyst system wherein said catalyst system comprises cobalt in a rangefrom about 700 ppm to about 4500 ppm with respect to the weight of theliquid in the primary oxidation zone, manganese in an amount rangingfrom about 20 ppm to about 400 ppm by weight with respect to the weightof the liquid in the primary oxidation zone and bromine in an amountranging from about 700 ppm to about 4000 ppm by weight with respect tothe weight of the liquid in the primary oxidation zone.